Chemical modification of L-asparaginase with N, O-carboxymethyl chitosan and its effects on plasma half-life and other properties

E.coli L-asparaginase,an antitumor enzyme,was chemically modified with N,O-carboxymethyl chitosan to lower its artigenicity and increase its plasma half-life.The results showed that the modified L-asparaginase has almost the same apparent Km value as that of native enzyme.The modified L-asparaginase also showed a higher protease stability against trypsin and a-chymotrypsin.After being modified,the enzyme exhibited the complete loss of antigenicity towards antiasparaginase serum.In addition,the higher the molecular weight of modifying reagents,the better the effects on reduction of antigenicity.When tested in vivo,the plasma half-life of the modified enzyme (t1/2=40 h) was over 33 times longer than that of the native enzyme (t1/2=1.2 h).     

Decomposition of Transformer Oil Under Ultrasonic Irradiation During Degassing Process

In the degassing process of transformer oil with ultrasonic waves ,decompostition of the oil was observed.Light hydrocarbons,including methane,ethane,ethylene ,aceylene,propane etc,were found to be released continuously from the oil into headspace within a closed vial placed in an ultrasonic field ,The gases came from decomposition of hydrocarbon molecules under cavitation effect.     

氧氟沙星片剂和滴眼液中氧氟沙星对映体的毛细管电泳拆分及定量分析

采用环糊精及其衍生物为手性选择剂在CE上对氧氟沙星对映体进行了分离，研究了环糊精种类、浓度、分离电压、温度对分离的影响．重点考察了氧氟沙星的定量线性范围、检测限和重现性，在20-200mg／L浓度范围内，迁移时间重现性的相对标准偏差(RSD)控制在1．13％以内，峰面积重现性的RSD控制在4．3％以内，检测限为1mg／L．结果表明用20mmo1／L二甲基-β-环糊精(DM-β-CD)为手性选择剂，背景电解质为50mmo1／L Na2HPO4，pH＝3．0，不加有机添加剂情况下可得到较好的分离效果．同时，对氧氟沙星药品实样进行了分析，建主了一种市售氧氟沙星片剂和滴眼液中氧氟沙星对映体简单、快速的毛细管电泳分离、定量分析方法．     

醋酸十二铵的吸附和SiO2悬浮液的稳定性

（1）测定了醋酸十二烷基铵（DAA）在CAB－O－SIL上的吸附，其等温线属双平台或LS型[1－3，5]；（2）NaCl的存在使DAA的吸附增加．但不影响其低浓度下第一平台的吸附量；HCl的存在则在全浓度范围内抑制了DAA的吸附，（3）测定了CAB－O－SIL颗粒在上述各溶液中的悬浮液的稳定性；（4）根据表面形成小胶团的吸附理论（即二步模型产）[2，3，5，]，并借助电导跟踪溶液中发生的变化，满意地解释了吸附和聚沉的实验结果．     

繁峙煤镜质组的生烃特征与热解产物生成动力学研究

本文利用付立叶红外光谱（ＦＴＩＲ），热解气相色谱（Ｐｙ－ＧＣ）及热解气相色谱质谱（Ｐｙ－ＧＣ－ＭＳ）联用技术等分析手段，探讨了我国山西繁峙煤镜质组的生烃特征，鉴定了如气体烃、正构脂肪烃、苯酚、单环芳烃以及甲氧基酚类等热解产物６７种化合物。用相继等温热解法一级反应动力学模型，求取了热解产物如气体组分（Ｃ１￣Ｃ６）、轻烃（Ｃ７￣Ｃ１４）、重烃（Ｃ１５￣Ｃ３０）、正构脂肪烃（ｎＣｉ）、烷基芳烃、苯酚等的     

反应性乳化剂存在下的五元苯丙乳液共聚合

采用反应性乳化剂SE-10N,通过正交实验及单因素实验确定了以苯乙烯、甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸和丙烯腈为单体的五元无皂苯丙共聚乳液的组成及聚合工艺。所制得的无皂乳液稳定,其乳胶粒大小均匀,粒径为50~60nm,比同组成的有皂乳液乳胶粒的粒径稍小。乳液涂膜透明、硬度达H级;其硬度、耐水性及钙离子稳定性均较同组成有皂乳液的好。     

Investigation of Tomato Plant Defence Response to Tobacco Mosaic Virus by Determination of Methyl Salicylate with SPME-Capillary GC-MS

Headspace SPME was applied to investigation of tomato plant defence response to tobacco mosaic virus (TMV) by determination of compounds emitted from tomato plants at the extraction conditions of 25 °C and 15 min. It was found that TMV-inoculated tomato plant released large amount of methyl salicylate (MeSA) as response to TMV and MeSA concentration changed dramatically with time after inoculation. Gaseous MeSA as a signaling compound could induce in surrounding tomato plants to produce salicylic acid (SA) and synthesize and release MeSA. These results show that MeSA might be an airborne plant-signalling molecule in tomato plant response to TMV. The present method provided low detection limit of 2.0 ng L^–1 and needed little sample preparation time (15 min), so the method makes it easy to find the critical times of tomato plant response to TMV by fast determination of MeSA released from tomato plant.     

Synthesis,crystal structure and reaction of differentially ring-substituted titanocene dichlorides

Summary A new class of differentially ring-substituted titanocene dichlorides of the type CpCpTiCl₂ has been prepared by reacting CpM (M=Li, K; Cp=RC₅H₄) with CpTiCl₃ (Cp=MeOCH₂CH₂C₅H₄). The crystal structure of Cp(PhCEt₂C₅H₄)TiCl₂, the first example, has been determined by x-ray diffraction and refined to a final R factor of 0.0532 for 2304 reflections. The crystal belongs to the monoclinic space group C _2h ⁵ –P2₁/c with unit cell parameters:a 10.205(6),b 13.003(5),c 17.591(9) Å, 101.91(4)°, V=2284 ų, Z=4 and Dc=1.32 g/cm^–3. Replacement of one neomenthyl in bis(neomenthyl-cyclopentadienyl)titanium dichloride by one MeOCH₂CH₂ — raises the e.e. value from 5.8% to 11.2% in the catalytic asymmetric hydrogenation of 2-phenyl-1-butene.     

链段相容性对聚酯-聚醚多嵌段共聚物组成均一性的影响

<正> 由结晶型芳族聚酯为硬链段,无定型脂肪族聚醚为软链段的聚酯-聚醚多嵌段共聚物,是一类性能优良的热塑弹性体,本文研究链段相容性对这类聚合物组成均一性的影响,因此,合成了一系列不同链段结构的聚酯-聚醚多嵌段共聚物。 如硬链为聚对苯二甲酸乙二醇酯(PET)和丁二醇酯(PBT);软链段有聚乙二醇醚(PET)、聚丁二醇醚(PTMG)、聚二醇醚(PPG)和四氢呋喃同环氧丙烷的共聚醚二醇